1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/em_text.c Textsearch ematch
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8#include <linux/slab.h>
9#include <linux/module.h>
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/string.h>
13#include <linux/skbuff.h>
14#include <linux/textsearch.h>
15#include <linux/tc_ematch/tc_em_text.h>
16#include <net/pkt_cls.h>
17
18struct text_match {
19 u16 from_offset;
20 u16 to_offset;
21 u8 from_layer;
22 u8 to_layer;
23 struct ts_config *config;
24};
25
26#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
27
28static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
29 struct tcf_pkt_info *info)
30{
31 struct text_match *tm = EM_TEXT_PRIV(m);
32 int from, to;
33
34 from = tcf_get_base_ptr(skb, layer: tm->from_layer) - skb->data;
35 from += tm->from_offset;
36
37 to = tcf_get_base_ptr(skb, layer: tm->to_layer) - skb->data;
38 to += tm->to_offset;
39
40 return skb_find_text(skb, from, to, config: tm->config) != UINT_MAX;
41}
42
43static int em_text_change(struct net *net, void *data, int len,
44 struct tcf_ematch *m)
45{
46 struct text_match *tm;
47 struct tcf_em_text *conf = data;
48 struct ts_config *ts_conf;
49 int flags = 0;
50
51 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
52 return -EINVAL;
53
54 if (conf->from_layer > conf->to_layer)
55 return -EINVAL;
56
57 if (conf->from_layer == conf->to_layer &&
58 conf->from_offset > conf->to_offset)
59 return -EINVAL;
60
61retry:
62 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
63 conf->pattern_len, GFP_KERNEL, flags);
64
65 if (flags & TS_AUTOLOAD)
66 rtnl_lock();
67
68 if (IS_ERR(ptr: ts_conf)) {
69 if (PTR_ERR(ptr: ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
70 rtnl_unlock();
71 flags |= TS_AUTOLOAD;
72 goto retry;
73 } else
74 return PTR_ERR(ptr: ts_conf);
75 } else if (flags & TS_AUTOLOAD) {
76 textsearch_destroy(conf: ts_conf);
77 return -EAGAIN;
78 }
79
80 tm = kmalloc(size: sizeof(*tm), GFP_KERNEL);
81 if (tm == NULL) {
82 textsearch_destroy(conf: ts_conf);
83 return -ENOBUFS;
84 }
85
86 tm->from_offset = conf->from_offset;
87 tm->to_offset = conf->to_offset;
88 tm->from_layer = conf->from_layer;
89 tm->to_layer = conf->to_layer;
90 tm->config = ts_conf;
91
92 m->datalen = sizeof(*tm);
93 m->data = (unsigned long) tm;
94
95 return 0;
96}
97
98static void em_text_destroy(struct tcf_ematch *m)
99{
100 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) {
101 textsearch_destroy(EM_TEXT_PRIV(m)->config);
102 kfree(EM_TEXT_PRIV(m));
103 }
104}
105
106static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
107{
108 struct text_match *tm = EM_TEXT_PRIV(m);
109 struct tcf_em_text conf;
110
111 strncpy(p: conf.algo, q: tm->config->ops->name, size: sizeof(conf.algo) - 1);
112 conf.from_offset = tm->from_offset;
113 conf.to_offset = tm->to_offset;
114 conf.from_layer = tm->from_layer;
115 conf.to_layer = tm->to_layer;
116 conf.pattern_len = textsearch_get_pattern_len(conf: tm->config);
117 conf.pad = 0;
118
119 if (nla_put_nohdr(skb, attrlen: sizeof(conf), data: &conf) < 0)
120 goto nla_put_failure;
121 if (nla_append(skb, attrlen: conf.pattern_len,
122 data: textsearch_get_pattern(conf: tm->config)) < 0)
123 goto nla_put_failure;
124 return 0;
125
126nla_put_failure:
127 return -1;
128}
129
130static struct tcf_ematch_ops em_text_ops = {
131 .kind = TCF_EM_TEXT,
132 .change = em_text_change,
133 .match = em_text_match,
134 .destroy = em_text_destroy,
135 .dump = em_text_dump,
136 .owner = THIS_MODULE,
137 .link = LIST_HEAD_INIT(em_text_ops.link)
138};
139
140static int __init init_em_text(void)
141{
142 return tcf_em_register(&em_text_ops);
143}
144
145static void __exit exit_em_text(void)
146{
147 tcf_em_unregister(&em_text_ops);
148}
149
150MODULE_DESCRIPTION("ematch classifier for embedded text in skbs");
151MODULE_LICENSE("GPL");
152
153module_init(init_em_text);
154module_exit(exit_em_text);
155
156MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
157

source code of linux/net/sched/em_text.c